YIELD AND CHEMICAL QUALITY OF CHEPIL (Crotalaria longirostrata Hook. & Arn) FORAGE AT DIFFERENT SEEDING DENSITIES AND CUTTING FREQUENCY

Abstract

Ruminant grazing in the tropics requires supplementation given the nutritional characteristics of pastures to cover protein needs. The objective of this research was to evaluate the yield and chemical quality of chepil (Crotalaria longirostrata Hook. & Arn) forage at different seeding densities and cutting frequencies to obtain the optimum harvest time. The experiment was set up in a completely randomized design with three replications. The treatments were planting densities T1: 200 000; T2: 100 000; and T3: 50 000 plants ha-1. The variables evaluated were: dry matter yield, morphological composition, growth rate, leaf:stem ratio, intercepted radiation, plant height, crude protein, neutral detergent fiber, acid detergent fiber, dry matter, and ash. For the 64-day cutting frequency, the three densities presented the highest yield with 3406, 3500, and 4200 kg MS ha-1, for 200 000, 100 000 and 50 000 plants ha-1, respectively (p < 0.05). PC decreased (p < 0.05) in T2 and T3 (23 %) in comparison to T1 (24 %). The planting density with the highest percentage of crude protein was 200 000 plants ha-1 with 24 %. The densities of 100 000 and 50 000 plants ha-1 presented a lower crude protein percentage, with 23 % (p < 0.05). It is concluded that the optimum cutting time is at 36 days of regrowth, when the chepil is planted at a density of 100 000 plants ha-1, and harvested at the frequency of 36 days of regrowth, since 95 % of intercepted radiation and better quality between yield and chemical characteristics, mainly crude protein, are obtained.